/Engine/Source/Editor/MeshPaint/Public/IMeshPaintMode.h
FEdMode: Called when a key is pressed
virtual bool InputKey ( [FEditorViewportClient](API\Editor\UnrealEd\FEditorViewportClient) * InViewportClient, [FViewport](API\Runtime\Engine\FViewport) * InViewport, [FKey](API\Runtime\InputCore\FKey) InKey, EInputEvent InEvent )